Proposal of pancake axial-air-gap-type self-excited wound-field synchronous motor

This paper proposes a pancake type synchronous motor where the space harmonics power is effectively utilized for the field magnetization instead of the permanent magnets. The pancake axial-gap structure, i.e., a single stator with double rotor configuration, can take great advantage to improve the mutual inductance which is indispensable for self-excitation of the magnet field. The advantages of the proposed motor in terms of the torque density is clarified with the FEM based simulation results. In addition, preliminary experimental test result is demonstrated from the viewpoint of the principle of self-excitation.